Moving Shoulders on a Case

Discussion in 'Reloading' started by statjunk, Jun 27, 2010.

  1. statjunk

    statjunk Well-Known Member

    Messages:
    219
    Joined:
    Jul 15, 2009
    Hello,

    I perplexed about something and would like to see if someone can explain this to me. So I recently subscribed to the bumping the shoulders back concept over the neck sizing concept. Since I'll be doing this I decided that I would dedicate one full length sizing die to this particular rifle and then just lock the die down.

    So I have a bunch of fire formed brass. I take it and I size. Not what I need to get to so I dialed the die down and sent the case back in. No change. So I grab another piece of brass and send it into the die and it is different from the first.

    So basically what I've found is that I can't change the sizing once I've sized the brass. It took me seven pieces of brass to get it right. Once I got it right I was able to produce as many identically sized pieces as I wanted.

    Is this what is supposed to happen? Why?

    I'd expect to be able to move the brass as many times as I want. As an example I had one piece of brass that was .007 under SAAMI I sent it up into the die after I got it all set and produced many .002 under SAAMI pieces but I wasn't able to move this one. Is this what is supposed to happen?

    If I haven't explained clearly please let me know and I'll try again.

    Thanks

    Tom
     
  2. Ridge Runner

    Ridge Runner Well-Known Member

    Messages:
    987
    Joined:
    Dec 13, 2002
    thats known as springback!, it happens because that piece of brass is harder and more brittle than others, you size it down the same as the others but it springs back more closer to its original size, thats why its advantageous to you to keep all your brass the same, load'em up the same amount of times, shoot them all before reloading them again, keep them all the same make, lot # and such.
    RR
     

  3. statjunk

    statjunk Well-Known Member

    Messages:
    219
    Joined:
    Jul 15, 2009
    RR,

    I think you miss read the question. This is about sizing. This is about when I'm sizing and I've pushed the shoulder beyond where it should be I can't seem to move it again.

    Can you take a second to re-read the post?

    I've come across this because I'm no longer neck sizing. I'm bumping the shoulders back .002.

    Thanks

    Tom
     
  4. Ridge Runner

    Ridge Runner Well-Known Member

    Messages:
    987
    Joined:
    Dec 13, 2002
    ok, the piece that was .007" under size, will not get bigger by resizing ( hope this is what your wanting) now if it will go off it'll be back to chamber size afterwards, if it will not go off, you'll hafta pull the bullet and resize it up one calber then size it back down. this makes a false shoulder to hold the headspace while its formed in the chamber.
    RR
     
  5. Mikecr

    Mikecr Well-Known Member

    Messages:
    4,263
    Joined:
    Aug 10, 2003
    Let me try RR
    statjunk, go out and kick a fender on your beamer.
    Notice this did not leave an actual footprint..
    It dented a little, but the fender sprungback some, right?
    You think kicking it again would reduce the dent?

    Now while your car is out for repairs, re-read your basic reloading book, or search the forum for anything in the world to be learned.
     
  6. Buffalobob

    Buffalobob Writers Guild

    Messages:
    5,085
    Joined:
    Jun 12, 2001
    A full length die is not a shoulder bump die. You need a body die.
     
  7. WRG

    WRG Well-Known Member

    Messages:
    133
    Joined:
    Nov 25, 2008
    Tom

    Check this tool out.

    Innovative Technologies - Reloading Equipment

    This tool will allow you to set up your sizer die the same every time. Though most shooters feel they need headspace off the shoulder the fact is if your rifle has the proper HS from the case head to the bolt face, +.002 / +.003, there is no need to even touch the shoulder, +.001 is generally all that is needed.

    I cringe at the thought of even touching the shoulder and disturbing my perfectly fire form cases that match my chambers dimension exactly. Not only does this practice of bumping the shoulder back play hell with run-out with the case neck, it also adds way more HS than is necessary which over works the brass. Larry's sales pitch is this gage will help you accurately set the shoulder back and it will, I on the other hand use it to make sure my die is not touching the shoulder. I find if I only re-size the neck and the body of the case, after two firings, my die barely touches the body and the case shoulder will stay true to my chambers OAL measurement. Every case will measure the same at the shoulder as long as I am using the same powder charge. If I'm trying to work-up loads the pressures are always changing and that will be apparent, as the shoulder measurements will not be stable. However, once I settle on a charge that is showing promise all my cases will measure the same and dialing in the load is real simple.

    If you already have a way to accurately measure your case shoulder you could give this a try. I own Larry's HS gage because it makes measuring fast, easy and can be used to take other measurements as well.

    WRG
     
  8. Fitch

    Fitch Well-Known Member

    Messages:
    478
    Joined:
    Aug 5, 2009
    Reading your original post, which is a bit confusing, I think what you are saying is that you bumped the shoulders back 0,007" on a piece of brass. More than you wanted. So you readjusted the die to bump them back less, put the same brass in the die and it was still too short, but brass you hadn't sized before adjusting comes out where you want it to. If I'm understanding this correctly, you made the original post because you find this confusing.

    So I'll explain. You can only make shoulders shorter with a full length sizing die. You can't make the shoulders longer by not pushing it in the die as far, which is what you are apparently trying to do.

    If you push the shoulder back .007", adjusting the die up 0.005" and putting it back in the sizing die again won't make the shoulder longer on the brass that was too short but it will properly size brass that wasn't too short.

    Bottom line, shoulder bumping in the die is a one way process. If you push them back too much in the die you need to fire them to get them back to chamber length.

    Fitch
     
  9. statjunk

    statjunk Well-Known Member

    Messages:
    219
    Joined:
    Jul 15, 2009
    removed because Fitch answered it.

    Tom
     
    Last edited: Jun 28, 2010
  10. statjunk

    statjunk Well-Known Member

    Messages:
    219
    Joined:
    Jul 15, 2009
    Fitch,

    This is exactly my question. So it is a one way process. I thought the expander ball would pull the shoulder back. Guess not.

    This is kind of disappointing in a way because it can become an awful mess to deal with the different number of fired brass. Not to mention I've just lost pieces in my current lot.

    Thanks for reading the post.

    TT
     
  11. statjunk

    statjunk Well-Known Member

    Messages:
    219
    Joined:
    Jul 15, 2009
    BB,

    I was told that I could bump with a full length sizer. Is this not true? Can others please chime in on this?

    Thanks

    Tom
     
  12. boomtube

    boomtube Well-Known Member

    Messages:
    1,595
    Joined:
    Oct 8, 2007
    'I was told that I could bump with a full length sizer. Is this not true? Can others please chime in on this?;

    Certainly you can "bump" with an FL die, you bumped the shoulder on the first one back .007". But, you also sized the neck and that isn't what you want from a body die, a bump die that sizes the neck is called a full length sizer die.
     
  13. statjunk

    statjunk Well-Known Member

    Messages:
    219
    Joined:
    Jul 15, 2009
    Boom,

    So if I'm using a FL sizing die to bump the shoulder and size the neck is that all that is happening or is it also sizing the case all the way down to the case head?

    I want the neck sized and shoulder moved. Is this "all" that I'm accomplishing?

    Thanks

    Tom
     
  14. WRG

    WRG Well-Known Member

    Messages:
    133
    Joined:
    Nov 25, 2008
    It sizes the neck, bumps the shoulder back "if you want it to" and sizes the body. That's why it is called a full length sizer die. :rolleyes:

    I would be curious to know what your reasoning is for opting to bump the shoulder. Is it because your cases are too long "at the shoulder" and you can not close the action if you don't? Or is it because your rifle has "NO" headspace at the bolt face? If the latter is the problem than a gunsmith should have a look at it and correct the issue. Relying on headspace off the shoulder can be a very disappointing situation in many aspects. But if your working with a hunting rifle and are only looking for minute of deer, you should be able to get that.

    WRG